1. Field of the Invention
The invention relates to a power-saving system that saves electricity while comprehensively controlling power supplied to each of a plurality of electronic devices equipped for an integrated system and, more particularly, to an in-vehicle power-saving system and a control method for the same, which save electricity while controlling the power supply status to each of the plurality of in-vehicle electronic devices depending on a usage situation of the integrated system.
2. Description of the Related Art
Japanese Patent Application Publication No. 2006-330843 (JP-A-2006-330843) describes an image input-output apparatus that has multiple functions, such as a printer, a scanner and a facsimile. The image input-output apparatus stops supply of power in order of increasing frequency of usage to thereby achieve energy savings.
In addition, Japanese Patent Application Publication No. 2000-215100 (JP-A-2000-215100) describes an apparatus that controls power supplied to each of a plurality of areas in a storage device and that stops supply of power to an area of which the frequency of usage is low to thereby achieve energy savings.
In addition, Japanese Patent Application Publication No. 2006-236532 (JP-A-2006-236532) describes an apparatus that controls power supplied to a plurality of AV devices, such as a DVD drive, a hard disk drive, a tuner, a ghost reduction circuit, and a LAN adapter, and that stops supply of power to AV devices that are not operated for a predetermined period of time to thereby achieve energy savings.
In addition, Japanese Patent Application Publication No. 2004-171553 (JP-A-2004-171553) describes a battery-powered ETC in-vehicle electronic device having a normal mode and a low power consumption mode. The ETC in-vehicle electronic device includes a wake-up circuit unit that switches the low power consumption mode to the normal mode, and supplies power to only the wake-up circuit unit in the low power consumption mode to thereby achieve energy savings.
The ETC in-vehicle electronic device additionally stops supply of power to the wake-up circuit unit to further achieve energy savings when the ETC in-vehicle electronic device recognizes that a shift range is set at any one of “P (parking)”, “N (neutral)” and “R (reverse)”, when no toll road is included in a recommended route searched by a navigation system, or when no ETC gate is present around a current location of a host vehicle even when a toll road is included in the recommended route. In such conditions, the vehicle is stopped or travelling backward or no ETC gate is present. Therefore, it is not necessary for the ETC in-vehicle electronic device to shift into the normal mode, and it is not necessary for the wake-up circuit unit to monitor a situation.
However, any apparatuses described in JP-A-2006-330843, JP-A-2000-215100 and JP-A-2006-236532 just passively control a method of supplying power on the basis of the frequency of usage or state of usage of each power supply target for a long period of time and cannot handle a case where the use of each of power supply targets discretely changes.
In addition, the ETC in-vehicle electronic device described in JP-A-2004-171553 controls only power supplied to the ETC in-vehicle electronic device itself, and is able to handle only limited and fixed conditions, such as when the shift range is set at “P (parking)”, “N (neutral)” or “R (reverse)” or when the navigation system outputs a recommended route. This also limits the energy-saving effect.